Device for truing and dressing grinding worms



Dec. 2, 1952 A. RICKENMANN 2,619,950

DEVICE FOR TRUING AND DRESSING GRINDING WORMS Filed Feb. 16, 1948 12 Sheets-Sheet l 1952 A RICKENMANN 2,619,950 DEVICE FOR TRUING AND DRESSING GRINDING WORMS Filed Feb. 16, 1948 12 Sheets-Sheet s Dec. 2, 1952 A. RICKENMANN DEVICE FOR TRUING AND DRESSING GRINDING WORMS 12 Sheets-Sheet 4 Filed Feb. 16. 1948 AFN Dec. 2, 1952 A. RICKENMANN 2,619,950

DEVICE FOR TRUING AND DRESSING GRINDING WORMS Filed Feb. 16. 1948 12 Sheets-Sheet 5 A. RICKENMANN DEVICE FOR TRUING AND DRESSING GRINDING WORMS Dec. 2, 1952 Fild Feb. 16. 1948 12 Sheets-Sheet 6 Dec. 2, 1952 A. RICKENMANN DEVICE FOR TRUING AND DRESSING GRINDING WORMS 12 Sheets-Sheet -7 Filed. Feb. 16. 1948 Y Dec. 2, 1952 -A. RI-CKENMANN 2,619,950

DEVICE FOR TRUING AND DRESSING GRINDING WORMS Filed Fb. 16, 1948 l2 Sheets-Sheet 9 Dec. 2, 1952 A. RICKENMANN 2,619,9

DEVICE FOR TRUING AND DRESSING GRINDING WQRMS Filed Feb. 16, 1948 12 Sheets-Sheet 10 Fig .13

1952 A. RICKENMANN 2,619,950

DEVICE FOR mums AND DRESSING GRINDING WORMS Filed Feb. 16. 1948 l2 Sheets-Sheet 11 Fig.14

Dec. 2, 1952 RlCKENMANN 2,619,950

DEVICE FOR TRUING AND DRESSING GRINDING WORMS Filed Feb. 16. 1948 12 Sheets-Sheet 12 Fig.15

Patented Dec. 2, 1952 DEVICE FOR TRUING AND DRESSING GRINDING WORMS Alfred Rickenmann,

Switzerland, assigno Kusnacht, near Zurich, r to Reishauer-Werkzeuge A.-G., Zurich, Switzerland Application February 16, 1948, Serial N 0. 8,695

19 Claims.

The invention relates to improvements in devices for truing and dressing the worm-shaped grinding wheel of gear grinding machines which produce gear teeth.

It is an object of the present invention to employ as truing and dressing tools press rolls and non-rotatable tools carrying diamonds. The profile of the grinding worm is preshaped or reconditioned by means of a press roll and then the finish or final dressing of the profile is accomplished by means of diamonds which latter work upon the sides of the profile of the grind ing worm helix and produce the desired grinding surfaces with great accuracy.

A principal object of the present invention is to provide novel means for controlling the truing and dressing tools.

Another object of the invention is to provide a press roll with an automatically actuated feed device. Furthermore, means are provided for preventing a rapid wear of the highly stressed press roll.

It is also an object of the invention to provide means which enable the diamond tools to be moved parallel to the sides of the profile of the grinding wheel.

Still another object of the inventionis to provide means for oscillating the diamonds during their engagement with the grinding worm to be dressed. This oscillating movement of the diamonds is of advantage and insures a clean and smooth dressing of the grinding worm.

It is also an object of the invention to provide means for producing a grinding worm which is particularly adapted to grind gears which are subjected to high loads. Gears of this type are frequently ground somewhat thinner at their head portions as would be required by the involute which determines the standard or normal shape of the gear teeth. It is, therefore, possible to employ the dressing device of the invention for producing modified profiles on grinding worms so that the latter are particularly suitable for grinding gears having the above mentioned modified gear teeth.

Other objects of the invention will be specifically pointed out in the description forming a part of this specification, but it is to be understood that the invention is not limited to the embodiment herein described, as various forms may be adopted within the scope of the appended claims. The drawings illustrate by way of example one embodiment of the truing and dressing device of the invention.

In the drawings:

shows the diamond dressing tools in engagement with a grinding worm.

Fig. 4 is a cross sectional view on the line IIII of Fig. 3.

Fig. 5 is a cross sectional view on the line III-III of Fig. 3.

Fig. 6 is a cross sectional view through the diamond tools on the line IV-IV of Fig. 3.

Fig. 7 is a plan view and a partial sectional view on the line V-V of Fig. 8 and illustrates a press roll device mounted on the grinding carriage.

Fig. 8 is a sectional view on the line VI--VI of Fig. 7 and illustrates certain members of the automatic feed device for the press roll.

Fig. 9 is a sectional view on the line VIIVII of Fig. 7 and illustrates additional feed members of the feed device and the drive members for the press roll.

Fig. 10 is a cross sectional view of the automatic feed device on the line VIII-VIII of Fig. 8 and line IX-IX of Fig. 9 respectively.

Fig. 11 is a diagrammatic illustration of the operation of the diamond tools during the dressing of a grinding worm employed for standard gear teeth.

Fig. 12 is a diagrammatic illustration of the operation of the grinding machine when the press roller is used for preshaping or reconditioning of the grinding worm.

Fig. 13 is a diagrammatic illustration of the hydraulic control device when the truing tool performs its working pass.

Fig. 14 is a diagrammatic illustration of the hydraulic control device when the truing tool executes its return pass and,

Fig. 15 is a diagrammatic illustration of the hydraulic control device when the truing tool is inoperative.

Drive mechanism Referring to the drawings, particularly Fig. 2, the frame 3 of the gear grinding machine is provided with guide tracks I and 2 on which a mounted in a bore AiII of the carriage Ci.

grinding carriage A is slidably mounted. The grinding carriage 4 is adapted to be adjusted along the guide tracks I and 2 by conventional means which are not illustrated because they do not have any particular bearing on the present invention.

An electric motor 5 (Figs. 2 and 3) is attached by means of a flange to the grinding carriage s and is operatively connected by a sleeve 5 (Fig. 3) with the grinding wheel spindle l. The latter is supported rotatably in the bearings 8 and 9 and nular end face H2 of the spindle l and with its other end against the end face III of the spur gear II and urges the spur gearli continuously to the left (Fig. 3). A block I3 engages the annular guide groove I I I2 of this spur gear II and is rotatably attached to a lever I4 which is fixedly attached to one end of a short shaft I5. rotatably ihe other end of the shaft It extends outwardly of the carriage 5 and has fixedly attached thereto a lever I5 which is provided with a handle I'I. The handle 11 has mounted thereon an adjusting pin I8 which is slidably mounted in a transverse bore of the lever I5 and is urged by a spring mounted in this bore downwardly in a direction in which the outer end i8lI of thepin I8 is urged against the outer surface of the carriage 4 and is adapted to be inserted selectively in two sockets 22 and 23 (Fig. 4) which indicate two diiferent operating positions A and B of the shaft IS. The center portion IBI I of the shaft it which is mounted in the bore 4H is provided with two radial passages I5I2 and ISI3. Both of these rafdialpassages are arranged in the same plane with a conduit 25 and with a drain passage 2| (Fig. 14) and upon proper positioning of the shaft It the conduit 29 can be connected with the passage 2|.

It is believed to be apparent from the above that by adjusting the lever [5 the spur gear II may be shifted to two different positions which are indicated by the sockets 22 and 23 anddesigmated with A and B respectively. When the lever I5 is adjusted to the position A the outer end I8l I of the adjusting pin I8 enters the socket 22 and thereby holds the lever E5 in this position. The spur gear II in this position is in engagement with a spur gear 25 (Fig. 3) and the coupling tooth IIII of the gear II is in engagement with a coupling tooth 26 of a gear 26 concentrically arranged about the spindle i. This A position is used when the grinding worm is to be trued or dressed, while the 3 position of the lever I5 is used when the grinding worm It is used for grinding gears and rotates with a high speed- In the latter case the grinding wheel spindle i is driven by the electric motor 5. When the electric motor 5 drives the grinding wheel spindle "I as just mentioned the end Ifil I of the pin I8 is in the socket 23 and the spur gear Ii rotates idly, i. e. it is out of engagement with any driven element.

An electric motor 21 is mounted on the cover 28 and is used for driving the truing device. The'two electric motors 5 and 21 are connected with each other in such a manner that the same cannot be put into operation both at the same time. These means are of conventional nature and are not disclosed in detail.

The downwardly projecting end 21H (Fig. i) of the armature shaft of the electric motor 21 has attached thereto a worm 29 which is in mesh with a worm gear 5%). The latter and the spur gear 25 (Fig. 3) are fixedly mounted on a shaft 3| which is rotatably mounted in the bearings 4 i 2 and M3 and is secured against axial movement. The spur gear 25, as has already been mentioned, is in mesh with the spur gear I I when the latter has been shifted to the position shown in Fig. 3, in which position the grinding worm I5 is to be trued and dressed. In this position the gear II, by means of its coupling tooth MN, is connected with the coupling tooth 25H of the spur gear 25 which is rotatably supported with its two hub members in two bearing sleeves 32 and 33 which latter are secured by set screws 35 and 35 against axial displacement. The spur gear 28 is continuously in engagement with a relatively wide spur gear 36 which is rotatably mounted on a stub shaft 3'! secured fixedly in a bore 4 I4 of the carriage 4. The two annular end faces M5 and 3III prevent an axial displacement of the spur gear 56. The latter is also in engagement with a spur gear 38 which is mounted for axial movement on a shaft 39 (Fig. 3). The hub of the gear 38 is provided with an annular guide groove 38% i and with a number of coupling teeth 3812 and the end face of the gear 38 opposite its hub is provided with a single coupling tooth 3M3. The shaft 39 is rotatably mounted in the bearings 49 and 4| and carries in addition to the spur gear 38 a short sleeve 42 provided on its end facing the gear 38 with a coupling tooth 42H. Furthermore, two spur gears 43 and is are mounted on the shaft 39. The spur gear 44 is mounted nonrotatably and exchangeably on the outer, end 39H of the shaft 39. The gear ill forms together with three other spur gears 45, 45 and (i1 (Fig. 3 a change speed gear the ratio of which is selected according to the pitch of the grinding helix on the grinding worm I I which is to be produced or dressed.

A lever 5| (Fig. 4) has attached thereto a pin 50 which carries rotatably a block .9 which is fitted in the annular groove 38H of the gear 38. This lever 5| is fixedly attached to the inner end 53II of a short shaft 53 which is rotatably mounted in a bearing MS of the carriage 4. The outer end 53 I 2 of the shaft 53 has fixedly attached thereto a similar lever 52 which also has rotatably attached thereto a block 55 by means of a pin 55. The block 54 engages a groove 56| I provided in a control piston 56 (Figs. 2, 5, 14, 15, 16).

A control ring 51 (Figs. 3, 5, 14, 15, 16) is rotatably mounted on the sleeve 52 and is secured against axial displacement by the annular end faces QZIZ and MIMI (Fig. 3). The control ring 51' is provided with a radial bore 51H (Figs. 5, 14, 15, 16) the outer end of which is closed by a screw plug 55. The bore 51 contains a helical spring 60 and a block 59 which latter is continuously urged by the spring 65 against the cylindrical surface of the sleeve 42. The control ring 57 is provided diametrically opposite of the radial bore 5'III with a slot-like recess 5H2 extending at right angles to the shaft 39. In this recess is pivotally secured one end of a link GI by means of a pin 63. The other end of the link Si is connected pivotally by means of a pin fiswith a control piston 62 which is slidably mounted in the control block I9 transversely to other pistons 56, I4 and I6 therein.

cumference of the portion 82I has The spur gear 43 is arranged between annular end faces 39I2 and 4I5 (Fig. 3) and thereby is prevented from moving axially with respect to the shaft 39 on which it is loosely mounted. The gear 43 meshes continuously with a spur gear 48 and is provided on its end face directed toward the hub of the gear 33 with a number of coupling teeth 43 I2. The spur gear 48 and also the change speed gear 47 are keyed to a guide screw spindle 65. The latter has mounted thereon fixedly a sleeve 66. The end face 66I I of this sleeve 66 and the annular shoulder I55II on the guide screw spindle prevent an axial displacement of the guide screw spindle 65, while the bore 8! forms a bearing for one end of the guide screw spindle 65. .The portion of the guide screw spindle 65 to the right of an annular collar 65I2 thereon is provided with a thread 65I3 which is in threaded engagement with the interiorly threaded sleeve 68. The latter is axially slidable in a bore I provided in the carriage 4 and carries on its outer circumference a tongue 69 which prevents a rotation of thesleeve: 68 in the carriage 4. The end face 68H of the sleeve 68 has attached thereto a cover 'II (Figs. 1,3 and which is held in place by screws 'II2. An axial projection on the cover II is provided with a T-shaped groove TI II (Figs. 2 and 3). and a laterally extending portion I2 of the cover lI carries a control pin 73 which extends parallel to the axis of the guide screw spindle 85, is attached to the portion I2 at 'III2 and projects into an axial bore 14 (Figs. 14, 15 and 16) of the control piston '04. The piston I4 carries a transverse stop in the form of a screw I5 the inner cylindrical end 'I5II of which projects into a longitudinal groove 73 provided in the control pin I3.

The control block I9 (Figs. 2, 3 and 5) is attached to the rear wall of the grinding carriage 4 by four screws I5. The block I 9 in addition to the already mentioned pistons 56, 62 and I4 also contains a main control piston 16 (Figs. 5, 14, 15, 16). The two opposite sides of the block I9 are provided with covers I1 and I8 (Fig. 3). The purpose andmode of operation of the four pistons 56, 62, I4 and IE will be explainedhereinafter in connection with the other control members.

Feed mechanism The grinding carriage 4 is provided with two guide tracks I9 and 80 (Fig. 2) which extend at a right angle to the axis of the grinding wheel spindle I and carry a carriage 8| for moving the truing tools toward and away from the grinding worm I0. A piston 82 is arranged in a cylindrical bore 84 arranged in the carriage 4 (Fig. 8 between the two guide tracks 19 and 80. The piston 82 is provided on one end with a reduced shaft-like portion 92! which is slidably supported in a bore 85 (Fig. 8) which is in axial alinement with the bore 84. The bore 84 at the end facing the grinding worm I0 is closed by a cover 8 3. The reduced shaft-like portion MI is provided with a central axial bore 822 and the outer circut therein two longitudinal grooves 823 and 824. The outer end face of the shaft-like portion 82I has attached thereto a nut 91 by means of screws 88. The longitudinal groove 323 is in communication with a conduit 89 and is of such a length that only a small portion S extends into the annular chamber 84I when the piston 82 rests against the end face 86I of the cover 80. A set screw 90 (Fig. 8) is arranged in the grinding carriage 4 in such a manner to project with its inner end into the longitudinal groove 824 of the shaftlike portion MI and thereby a rotation of the piston 82 is prevented. The nut 81 is in threaded engagement with a spindle 9| which is employed for adjusting the carriage BI and carries nonrotatably thereon a spur gear 92. The outer end of the spindle 9| has a hand wheel 93 attached thereto; The spindle 9I is rotatably mounted in abore 8II of the carriage BI and is prevented from moving axially with respect to the carriage 8| by the annular end faces 93I and 9| I.

The carriage 8| is also provided with an automatically operable feed spindle 94 (Figs. 2 and 9) which is arranged parallel to the manually operable feed spindle M. The feed spindle 94 is rotatably mounted in a bore 8I2 of the carriage BI and extends slidably through the bore 95I of a ratchet wheel 95 having arelatively long hub. The feed spindle 94 is secured against axial movement by its annular end face 94I and by a washer secured by a screw 9! to the end of the spindle 94. A spur gear 98, which is axially movably mounted on the feed spindle 94, has a hub provided. with an annular groove 98I into which a pin 99 extends which is attached to a lever I00. The lever I00 is attached to a short vertical shaft IOI rotatably mounted in a bore 8I3 of the carriage 8| and has on its upper end a handle I02. By rotatably adjusting the handle I02 it is possible to shift the spur gear 98 along the feed spindle 94. A rotation of the handle I02 causes a rotation of the shaft IOI and of the lever I00 so that the pin 99 thereon is adapted to be moved to two different positions C and D (Figs. 3, 8 and 9). In the position C the spur gear 98 meshes with the spur gear 92. This is the position, as will be described presently, when the truing roller device is in engagement with the grinding worm I0 and the feed movements are executed by the automatic feed device (Figs. 7, 8 and 9). The position D (Figs. 1 and 3) is selected whenvthe diamond tools are used for dressing the grinding worm.

The feed spindle 94 is operatively connected with a ratchet device which includes the ratchet wheel (Figs. 9 and 10), a feed wheel I03, a piston I04 and a spring I05. The ratchet wheel 95 is rotatably supported in a bore I06 of the carriage 4 The feed wheel I03 is rotatably supported on the long hub of the ratchet wheel 95 and is positioned between the annular faces 952 and I06I (Fig. 9). An annular nut I01 attached to the outer end of the hub of the ratchet wheel 95 prevents axial displacements of the latter and of the feed wheel I03. The feed wheel I03 carries on a radial extension a pawl I08, a stop I09 and furthermore is provided with a gear segment I03 I. The pawl I 09 is arranged in a bore I032 (Fig. 10) the outer end of which is closed by a cover IIO. A spring III in the bore I032 urges the pawl I 08 continuously in engagement with the teeth of the ratchet wheel 95. The gear segment I03I (Fig. 10) engages a rack bar I04I on the piston I04. The piston I04 is axially slidably mounted in a vertical bore I I4 both ends of which are closed by the covers H2 and H3. The piston I04 is provided with an axial bore I042 in which is mounted a spring I05 which engages with one end the cover II 2 and continuously urges the piston I94 upwardly. The chamber II4I formed between the upper end of the piston I04 and the upper .cover I I3 communicates with the conduit .89 by means of the passage II5. The rotative movement of the feed wheel I93, or the so-called stroke of the piston I64 connected therewith, is determined by the position of the abutment screw H6. The latter is adjustably mounted in the grinding carriage 4 and is secured in the desired position by a lock nut I H. The operation of this feed device will be described presently in connection with the other control elements.

The carriage BI is provided with two upper guide tracks H8 and I I9 (Figs. 1, 8 and 9) which extend parallel to the axis of the grinding wheel spindle I. The guide tracks H8 and H3 are used for slidably supporting a carriage I which is adapted to support selectively either the truing roller device or the diamond dressing device. The body of the carriage I20 is provided with two parallel lengthwise extending bores I2I and I22 (Figs. 3, 8 and 9). The bore I22 extends entirely through the carriage I26 and has mounted therein two axially alined sleeves I24 and I25 (Figs. 2, 3 and '7) which are secured by set screws I21 and I28 against rotation and axial displacement. The sleeve I25 has an interior thread which is in engagement with a screw spindle I26 while the other sleeve I24 serve solely as a guide for the non-threaded portion of the spindle I26. The left hand end I26I of the screw spindle I26 (Figs. 2, 3 and 7) is shaped in such a manner with head and neck that it fits correctly and rotatably into the T-shaped groove IIII provided in the axial projection of the cover II. The right hand end I262 of the screw spindle I26 has attached thereto an adjustment knob I29 (Fig. 3). The other longitudinal bore I2I in the carriage I20 does not extend entirely through the carriage but terminates before one end of the same as shown at I2 II (Figs. 3 and 7) which numeral indicates the bottom of the bore I2 I. The bore I2I has mounted therein a long helical spring I33, one end at which rests against the bottom I2II and the other end projects outwardly from the bore and abuts against a plate I3I which is secured to the carriage 8| by screws I32 (Figs. 2, 3, and '7). The spring I continuously urges the carriage I20 to the left (Fig. 3).

The carriage 3| is provided with a raised center portion (Figs. 1, 2, 3, 8 and 9) which is used to support a device for controlling the diamond tools I54 and IE5. This device comprises a spindle I33 (Fig. 3) provided with a left hand thread I33I and a right hand thread I332 and which is rotatably supported in plates I34 and I35 secured to the ends of the center portion by means of screws I36 and I3l'. One end I335 of the spindle I33 projects outwardly from the plate I34 and carries fixedly thereon a hand wheel I38 provided on the circumference of its hub with a graduated scale I33I. A nut I39 is attached to the threaded end portion I334 of the spindle I33 and urges the hand wheel I38 against the end face I333 of the plate I34. The shoulders I336 and I332 prevent an axial displacement of the spindle I33. The two threaded portions I33I and I332 of the spindle I33 have mounted thereon adjusting blocks I46 and I4I respectively, which are fitted without any play between the upper cover I42 and the bottom face 8I4 of a recess formed in the raised center portion (Figs. 8 and 9). The sides Mill and Hill of the blocks I40, I4I facing the grinding worm IIi are provided with T-shaped tongues (Fig. 9) and, furthermore, these tongues are oppositely inclined with respect to a vertical plane extending through the axis of the spindle I33. The .T-shaped tongues on the adjusting blocks I and HM are in engagement with correspondingly formed inclined T-shaped grooves I43 and I44 which are formed on the side edges of two superimposed plates I45 and I45. These plates are held together by five screws I41 (Figs. 3, 8 and 9) and likewise are carefully fitted into the recess formed between the bottom face (H4 and the cover I42. The cover I42 is held in position by screws I43 (Fig. 8).

Truing and dressing devices The profile of the grinding worm I6 preformed or reconditioned by a roller device (Fig. 7) and for finishing the profile a diamond dressing device (Fig. 1) is used. Either one of these two devices may be mounted selectively between the guide shoulders I25I and I252 (Figs. 8 and 9) on the plane surface I263 of the carriage I25.

The roller device (Figs. 7, 8 and 9) comprises a casing I43 which is adapted to be secured to the carriage I23 by four bolts and nuts I53. The casing I49 is closed at one end by a cover I5I (Fig. '7) which is held in place by a number of screws I52. A short and strong shaft I53 is r0- tatably mounted in bearings I49I and I5II provided in one end of the casing I43 and in the cover I5I respectively. The shaft I53 carries a press roll I54 and also has keyed thereto the innor annular member I55 of an overrunning clutch associated with a worm gear I58. The press roll I54 is provided with a plurality of annular grooves I54I. The profile of these grooves corresponds to the profile of the thread on the grinding worm Ill. The walls of the grooves I54I are provided with radial grooves I542 (Fig. 8). The press roll I54 is held against an annular shoulder I533 of the shaft I53 by a nut I56 which is screwed upon the threaded portion I531 of the shaft I53. The annular member I55 of the overrunning clutch is mounted between the annular shoulders I534 and I432 (Fig. '7) and thereby is secured against axial displacement. In View of this construction it appears that the shaft I53 is held against axial displacement by the annular shoulders I492 and I5I2. The inner annular member I55 of the overrunning clutch carries a number of rollers I51 (Figs. 7 and 9) and also supports the worm wheel I53 which latter is in engagement with a worm I56. The arrangement of the rollers I51 is such that the same are adapted to establish a driving connection between the worm wheel I58 and the shaft I53 when the latter is at rest or rotates slower than the worm wheel I58. If, however, the shaft I53 is driven by the press roll I54 with a greater speed than the worm wheel I56 is driven then the rollers I5'I become ineffective and the inner member I55 of the overrunning clutch overruns the slower rotating worm wheel I58. The worm I53 is attached to the end of an armature shaft of an electric motor I69 which is attached in vertical position by means of a flange to the casing I49 (Figs. 8 and 9). The number of revolutions of this motor I35 and the transmission ratio of the worm gearing I53, I59 is so selected that the circumferential speed of the press roll I54 driven by the same is a little below the smallest possible circumferential speed of the grinding worm I6, when the latter is driven with reduced speed by means of the electric motor 21, which latter drives the worm gearing 23, 30, the shaft 3|, the spur gears 25, II and finally the spindle l.

The diamond dressing device comprises two plates I62 and I63 (Figs. 1 and 3) which contain the guide grooves I62I and I63I for the two diamond tools I64 and I35. The lower plate I62 is secured fixedly by means of four screws I66 to the carriage I 26 and is provided with two tongues I 61 (Fig. 3) extending parallel to the guide tracks IIS and I I9. The plate I63 is superimposed upon the plate I62 and is slidably fitted onto the tongues I61. The mating face between the two plates I62 and I63 is positioned in a horizontal plane which also passes through the axis of the grinding wheel spindle 1 (Figs. 1 and 3).

The diamond tool I64 is arranged in the guide groove I62I of the lower plate I62 (Figs. 1, 3 and 6). The groove I62I extends parallel to the side LM of the profile of the grinding worm I6. In similar manner the guide groove I63I extending parallel to the other side N-O of the profile of the grinding worm I6 is arranged in the upper plate I63 and contains the diamond tool I65. Both diamond tools I64 and I65 have inserted at their front end a diamond I68 and I69 respectively. The diamonds I68 and I69 are in most cases somewhat narrower than the side L-M or N-O, but their cutting edge extends absolutely parallel to the guide of the holder or the respective side of the profile of the grinding worm I6. Both diamond tool holders are provided each with two spring supporting plates I16 which are riveted in position and which are arranged in recesses I622 and I632 of the plates I62 and I63 respectively. Pressure springs I1I are arranged between the side walls I623 and I633 of the two recesses I622 and I632 respectively, and the plates I16. The pressure springs I 1| are effective to press the points I 6 and I65I of the two diamond tools I64 and I65 always without play against the control faces I46I and I45I of the plates I46 and I45 respectively.

For the adjustment of the diamonds I68 and I69 (Fig. 3) the upper plate I63 may be moved along the tongues I61. For this purpose the plate I63 is provided with two oblong holes or slots I635 and with a threaded socket I634 into which is screwed an adjustment spindle I12. The latter is rotatably supported by a projection I624 extending upwardly from one end of the lower plate I62 (Figs. 1 and 3). The adjustment spindle I12 carries on its outer end an adjustment knob I13 and two shoulders I13I and I12I prevent an axial displacement of the adjustment spindle I 12 in the projection I 624. The plate I63 is held in position by the two screws I14 passing through the slots I635.

Operation and functions of the control members In the following the operation of the truing and dressing devices and the functions of control members are described in succession and the manner of producing and dressing the profile of the grinding worm I6 will be explained.

When a new grinding disc having a cylindrical outer surface is to be subjected to the roller device or when a grinding worm having a defective or worm profile is to be reconditioned the following operating conditions are to be established:

The lever I should be in the position A so that the spur gears II and '25 (Figs. 3 and 4) are in mesh with each other. The handle I62 should be in the position C (Figs. 7, 8 and 9) so that the spur gears 92 and 96 are in mesh with each other.

The roller device is mounted on the carriage I26. Furthermore, for the sake of discussion it will be assumed that the control elements of the press roll are in the position as disclosed in Fig. 14. The electric motor 21 drives by means of the worm gearing 29 and 36 the shaft 3|, which latter drives the spur gears 25 the grinding wheel spindle 1 is is connected by the key I 6I with the gear II. Therefore, the grinding worm I6 is rotated with areduced speed as intended for the truning and dressing operation. Further, the spur gear II by means of the one tooth clutch IIII and 26 (Fig. 3) drives the spur gears 26, 36 and 38. The one tooth clutch 38I3 and 42 drives the sleeve 42 and therewith the shaft 39 because the latter is connected by the key I15 with the sleeve 42. The shaft 39 drives by means of the change speed gearing 44 to 41, the ratio of which has been selected according to the pitch angle of the uide screw spindle 65, and the latter rotates in the direction indicated by the arrow in Fig. 3. The spur gear 46 keyed to the guide screw spindle 65 drives the spur gear 43 which in this instance rotates idly on the shaft 39.

The rotation of guide screw spindle 65 causes an axial displacement of the sleeve 66 which is in threaded engagement with the guide screw spindle 65 but is prevented from rotating by the tongue 69. The sleeve 68 moves axially toward the right and thereby moves also the parts H and 13 toward the right because these parts are connected with the sleeve 68 (Fig. 3). This longitudinal movement is also transmitted to the screw I26 whose shoulder I263 is continuously in engagement with the cover H and thereby the carriage I26 connected with the screw I26 is moved toward the right and in this manner the roller device which is mounted on the carriage I26 is also moved toward the right.

It is assumed that the press roll I54 is in engagement with the grinding worm I6 as shown in Fig. 7. The grinding worm I6 in this particular operating condition acts as drive member for the press roll I54 and the circumferential speed of the press roll I 54 and of the grinding worm I0 are therefore alike. As already explained previously the number of revolutions of the shaft I53 will be greater than the number of revolutions which would be transmitted to the shaft I 53 by the electric motor I66 and the worm gearing I59, I59. Therefore, the overrunning clutch I55, I51 between the shaft I53 and the worm wheel I58 is inoperative, that is, the inner member I55 overruns freely the outer member consisting of the worm wheel I58.

The pressure fluid employed for controlling the truing and dressing devices is supplied by a gear pump I16 (Fig. 14) which. draws the fluid from a sump I11 and conveys it into the pressure line I18. The required pressure is adjusted by means of the pressure regulating valve I19 and is indicated by the pressure indicator I 86. The sump I11 and the parts I16, I19, I19 and I86 are preferably arranged in the base of the machine frame 3. The pressure fluid enters the chamber I6I of the control block I9 and from here enters the conduit I62 and is conducted to the cylindrical chamber I83 in which the piston 16 is slidably mounted. The piston 16 is maintained by the pressure fluid in its right hand end position. From the chamber I83 the pressure fluid enters the line I84 and the chamber I85, so that the piston 56 is pressed against the end face 18I (Fig. 14). The lever 52 whose position is controlled by the piston 56 in this operating condition points toward the right. The lever 52 which is attached to the shaft 53, therefore, also holds the lever 5I connected with the shaft 53 toward the right in which position the block 49 on the lever 5| and and II so that rotated since it which extends into the annular groove SBI I of the spur gear 38 holds the latter in the right hand end position in which the one tooth clutch til I, 3M3 is maintained in operative position. The result is that the above described driving connection of the guide screw spindle 65 is maintained. Another line I85 conducts pressure fluid from the chamber Hi3 into the annular groove iiZI of the piston 62 and from there into the line I8? and I33 so that pressure fluid enters the chamber S it of the feed device. Therefore, the piston 82 is moved toward the right (Figs. 8 and 1e) and the press roller lb i is urged against the grinding worm is because the piston 82 is operativeiy connected by means of the spindle 9i and the hand wheel 93 with the carriage 8i which latter supports the carriage I26 on which the roller device is mounted (Figs. 1, 8 and 14). When the distance between the piston 82 and the end face fiti (Fig. 8) is smaller than the predetermined distance T the pressure fluid can enter the chamber HM by means of the crack S, the groove S23 and the two passages se and I I5. The piston Hid (Fig. will then be urged continuously downwardly and its end face Wi 13 engages the cover H2. Accordingly, the rack Hi l! holds the feed wheel lei, by means of the gear segment 938 in that extreme end position in which the stop Hi9 is spaced from the abutment Hit a distance which is equal to the adjusted angle (p.

If, however, the distance between the end faces 8M and 826 is larger than the crack T then there is no communication between the chamber Bel and the groove This condition occurs when the depth of the profile produced by the press roll I54 on the grinding worm Ii] is smaller than the distance the roll I5 has been fed. When the automatically executed feed movements under these conditions would continue without interruption the possibility would exist that the difference between the produced depth of the profile and the feed movement would increase. When this would happen it would mean that certain damages would be produced because the press roll I5 1 would be able to enter into the grinding worm at various places with a different degree of depth, particularly when the material of the grinding worm is not of uniform hardness, and there would be produced a defective profile which is not uniformly round. The construction as proposed in the present invention, however, prevents such errors, because the automatic feed mechanism can only become active when the crack between the end faces fiiil and $25 is smaller than the predetermined small distance T.

The travel of the carriage IZil from the left hand side toward the right hand side, or in other word the working pass of the press roll I5 5 upon the grinding worm Ii] continues until the end l3 l2 (Fig. is) of the groove 'ISII engages the inner end 1 5 of the screw l5, whereupon the piston id is likewise moved toward the right. The pressure fluid now flows from the chamber IfiI into the passage E89 and into the chamber I96. The result is that the piston '45 is moved toward the left until it engages the end face ll I. The fluid in the chamber drains into the sump I'll over the passage i352 which has been disconnected from the line iii; by the just mentioned movement of the piston i i. In the left end position of the piston it the pressure fluid in the chamber I93 enters by means of the passage Ili the chamber 8 32 and moves the piston 82 therein rearwardly, that is toward the left hand side. This has the result that the press roll I5 2 is moved away from The radial movement of the press roll away from the grinding worm I0- is of a predetermined distance and is discontinued when the fiuid expelled from the chamber 8M into the passages I38 and Hi2 has filled the empty chamber i953. The volume of the chamber I95 is so selected that the truing and dressing tools, namely the press roller lEd or the diamonds as the case may be, are moved completely out of the range of the grinding worm The stroke U (Fig. 10) of the piston 22 is somewhat larger than the largest possible depth a of the profile. Shortly before the piston 82 has completed its stroke U the pressure fluid from chamber 842 enters the passage H33 and the chamber I9 3. The piston es moves toward the left until it engages the end face "5'52 (Fig. 14). The fluid in the chamber E is expelled into the passage Hit, the chamber ass and the passage I32. During the travel of the piston toward the left the lever 52 which with its block 56 engages the groove sen is moved in clockwise direction and thereby the shaft 53 carrying the lever 52 and the lever iii are also rotated in the same direction. This causes a movement of the spur gear 38 toward the left because the block engages the groove 38 of the spur gear This has the result that the one tooth clutch 52M and 3M3 is disengaged and that the tooth clutch 3M2 and 53 i 2 is engaged (Fig. 3). The guide screw spindle 5%; now is no longer driven by the one tooth clutch 22i! and 3323, the sleeve 52, the tongue N5, the shaft and the change speed gear d l il, but the guide screw spindle 55 is now driven by the spur gear 38, the tooth clutch 3H2 and i3i2 and. the spur gears it and At the same time the direction of rotation of the guide screw spindle is is reversed and its number of revolutions is substantially greater than during the previous. working pass of the carriage lit. Accordingly, the sleeve the cover ii and the control pin "13 mounted thereon are moved toward the left. Furthermore, the carriage I26 and the roller device mounted thereon is moved with increased speed under the action of the spring I39 also toward the left and this constitutes the return pass of the roller device. When the press roll lid becomes disengaged from the grinding worm I the number of revolutions of the shaft I53 decreases. As soon as the number of revolutions is substantially equal to the number of revolutions of the worm wheel E58 which is driven by the electric. motor 25%, which motor is continuously in operation during the use of the roller device, the overrunning clutch becomes effective the worm gear the, E59 takes over the drive of the shaft I53.

During the return travel of ie carriage In ith the press roll its thereon the guide screw spindle drives by means of the change speed gear ii, id, 55 and ii the shaft 39 and the sleeve mounted on the latter. The direction of rotation, however, is reversed from the direction of rotation which the shaft 33 has during the working of the carriage 528. Therefore, the sleeve causes now a rotation of the control ring 53 mounted thereon in counterclockwise direction in view of the fact that the spring 6!] urges the block at slightly against the surface of the sleeve 62. This causes a shifting of the linkage iii, 63 and E i and of the piston 62 connected therewith toward the right, namely from the position shown in Fig. 14 to the position shown in Fig. 15 or 16. As soon as the end face 522 of the piston 62 engages the outer wall of the carriage 4 the communication between pasthe grinding worm I9.

sages I 88 and I81 is interrupted (Fig. and a further rotation of the control ring 51 is impossible and the latter remains in its new position as. shown in Fig. 15 as long as the shaft 89 and the sleeve 82 continue to rotate in this reverse direction.

When the press roll I54 is moved away from the grinding worm I8, namely when the piston 82 (Fig. 8) moves toward the left (Fig. 8) the communication between the groove 823 and the chamber 8 is at once interrupted. However, the other end of the groove 823 is connected with the atmosphere. Under the action of the spring I85 (Fig. 19) the piston I84 will now be moved upwardly and expels the fluid from the chamber lI II through the passages II 5 and 89 and the groove 823 into the atmosphere, so that the fluid can drain into the sump I11. The rack I04! rotates by means of the tooth segment I 03I the feed wheel I 03 counterclockwise about the adjusted angle (p, that is, until the stop I09 engages the abutment screw I I8. The pawl I88 which is under the action of the spring III transmits during the above mentioned rotation of the feed wheel I83 the movement of the latterto the ratchet wheel 95. The latter is connected with the shaft 94 by the tongue 853 and the latter rotates the two spur gears 98 and 92 (Figs. 8 and 9) which latter is mounted on the spindle 9| provided the gears 98 and 92 are in mesh with each other which is the case as long as the lever I02 is in position 0. The spindle 9| is provided with a right handed thread and rotates during this phase of operation clockwise which results in a feed movement of the carriage 8| during which the press roll I58 is moved a step toward the grinding worm I0.

At the end of the return pass of the carriage I the cover 1I engages the end face 14I2 of the piston 14 and moves the latter toward the left into its original position (Fig. 14) Now pressure fluid again flows from the chamber I8I into the passage I82 and into the chamber I83 and moves the piston 18 toward the right until it engages the end face 182 (Fig. 1 1). The fluid in chamber 180 is expelled into the passage I89, the chamber I 96 and from here drains through the passage llll into the sump I11. At the same time the chamber I95 is emptied over the passage I08 which conducts the fluid into the sump I11.

At the same time pressure fluid from the chamber I83 is forced over the passage I84 into the chamber I 85 and causes the piston 56 to move toward the right until it engages the end face 18L This action takes place immediately after the piston 18 has been reversed and has reached the position shown in Fig. 14. When the piston 58 moves toward the right the fluid in the chamber I84 is expelled over the passage I 9 9 into the annular groove 208 in the piston 16 into the passage 28! which drains the fluid quickly into the sump I11. This is accompanied by a counterclockwise rotation of the two levers 52 and 5I which are attached to the shaft 53 and the spur gear 38 is moved again toward the right (Fig. 3) so that the tooth coupling 38I2 and 43I2 is disengaged. The return drive is thereby immediately interrupted, however, the one tooth coupling 38M and 42 is engaged almost immediately and the working pass is started again. The drive of the guide screw spindle 65 takes place again in the same manner as previously described, namely by means of the spur gear 38, the one tooth coupling 38I8 and 42I I, the sleeve 42, the key I15, the shaft 39 and the four change speed gears 44 to 41 inclusive.

cover II, the control pin 13 andthe carriage I28 are again moved toward the right in their working pass.

As soon as the piston 16 reaches its right hand end'position (Fig. 14) the passage I88 is connected with the chamber fluid entering the passage I88 irrthis position of the elements is unable to enter the passage I81 because the piston 82 still is held in its right hand end position (Fig. 15) and blocks the passage of the pressure fluid. The movement of the piston 62 toward the left takes place only after the one tooth coupling 38I3 and 42 has become engaged and has rotated the shaft 39 in a direction in which the carriage I20 travels toward the right. Only after the carriage I20 has already moved a small distance toward the right will the sleeve '42 become effective to rotate'the control ring 51 mounted thereon in clockwise di rection so that the linkage BI, 63 and 84 is able to move the piston 62 connected therewith toward the left, until the annular shoulder 623 engages the control block I8. As soon as this has taken place the pressure fluid in the passage I86 can again enter the annular groove 62I which establishes a communication between the passages I88 and I81 and then the pressure fluid can flow into the passage I88 and into the chamber 84I to move the piston 82 toward the grinding worm I0 until the press roll I54 engages the latter. The fluid in the chamber 842 is expelled into the passage 202 and into the annular groove 200 and from here reaches the drain passage 20I to be returned to the sump I 11. on the control system is again in the condition as shown in Fig. 14 and operates a previously described.

This operating cycle continues until the'desired depth a of the profile has been reached. All the operations described may be diagrammatically illustrated by means of a closed diagram as illustrated in Fig. 13.

In Fig. 13 the distance E-F illustrates the effective working pass P of the press roll I54 during which the latter is in engagement with the rotating grinding worm I 0. The grinding worm I0 determines the number of revolutions of the press roll I54 during this period and as previously described the overrun clutch I55, I51 is inoperative as long as the press roll I54 rotates faster than the outer portion of the overrunning clutch consisting of the worm wheel I58 which is driven continuously by the electric motor I60. In this phase of operation the control system is in the position shown in Fig. 14.

At the point F of Fig. 13 the piston 82 and therewith the press roller I54 is moved away from the grinding worm I0. The carriage I 20, however, continues to travel in its working pass direction toward the right. Only after the radial return movement F-G, namely the stroke U of piston 82 has been completed and the press roller I54 has been completely moved out of the range of the grinding worm ID the return pass starts at the point H. The return pass takes place with increased speed toward the left, namely during the distance HI. During this time the automatic feed adjusting device becomes operative and the feed spindle 9I is rotated one step. During this time the press roll I54 will be positively driven. by means of the engaged overrun clutch I55, I51 from the electric motor I60. During this phase of operation the position of In view of the" change of direction of rotation the sleeve 68, the

I83, but the pressure From this point the elements in the control system is as shown in Fig. 15;

At the end of the return travel, namely at the point I the carriage I20 again is caused to move toward the right. However, only after it has moved apredetermined distance in this working stroke the feed movement ofthe carriage 8I is started at the point K and is completed at the point E. This distance K-E denotes the stroke U of the piston 82. From this point on the press roll I54 is again in engagement with the grinding worm III. The number of revolutions ofthe press roller I54 will be somewhat higher than the number of revolutions which the motor I60 and the'worm gear I58, I59 is able to transmit to the press roll I54. Therefore, the overrunning clutch is rendered ineffective at the point E, that is to say, the inner member I55 of the overrunning clutch rotates faster than the outer member I58 and the clutch rollers I51 are ineffective. Since the circumferential speed of the press roll I54 before the point E is only a small amount smaller than the circumferential speed of the grinding worm I0, owing to the fact that the electric motor I60 drives the press roll I54, it will only be necessary to supply a, small amount of accelerating energy at the point E in order to'bring the press roll I54 to the same speed as the grinding worm II). If the motor I60 would not have been provided the press roll I54 would almost have no speed at all after it has completed its return pass from point H to I and it would be necessary to accelerate the press roll I54 at the point E from about zero to the circumferential speed of the grinding worm Ill. A considerable shock would be exerted when the rotating grinding worm I engages the substantially nonrotating roll I54 and such a shock would influence very detrimentally the quality of the profile to be produced. Not only would it be necessary to supply a considerable amount of acceleration energy in order to bring the press roll I54 to the desired speed, but the considerable amount of friction produced thereby would cause a substantial wear of the press r011 I54. Since, however, the present invention provides an electric motor'for driving the press roll I 3 before it engages the grinding worm If! any detrimental actions are reduced to a minimum and it is possible to produce very accurate and uniform F profiles on the grinding worm and the press roll which is employed will have a very long life.

The disclosed arrangement of the control members and the selected succession of the control movements permit the employment of very effective press rolls having a plurality of annular ridges. It is not necessary to make the working pass of the carriage I28 so long that the relativelywide press roll IE4 at the beginning and at the end of its working pass which is indicated by the distance EF comes completely out of, lateral engagement with the grinding worm Ill. But as shown, it is only necessary that one end of, the press roll I54 be arranged to extend somewhat from either end of the grinding worm Hi. In the illustrated embodiment of the invention the carriage I is able to'effect a complete work ing stroke P within the distance 'E-F (Fig. 13). One end portion ofthe press roll its will engage the grinding worm id at the point E and at the point P the press roller Ifid will be moved radiallyawa'y from the grinding worm Iii before the entire press roll I5 5 has moved laterally or axially away from the grinding worm II).

When the rolling'o'peration in which the press roll I54 engages the grinding worm I0 has to be interrupted or for any other reason has to be terminated, for instance, when the desired depth a of the profile has been reached it is advisable to move the lever I5 into the position B during the return travel of the carriage I20 (Fig. 15), that is, during the operating phase H-I (Fig. 13). When this is done the shaft It, the lever I 5 and the block. I3 in the groove III2 of the hub of 'spur gear II causes a shifting of the latter until its annular shoulder Hi3 engages the sleeve 6 (Fig. 3). In this position the spur gears II and 25 are disengaged from each other and, furthermore, the one tooth coupling IIII and 26 is disengaged. The result is that the grinding wheel spindle I, the grinding worm iii and the carriage I20 are stopped at once.

There is established, however, now a communication of the passages I83, I92 and 2G and the two radial pasages I5I2 and Ifil3 (Fig. 16) in the shaft Iii with the drain passage 2i. As is apparent from the Figs. 15 and 16 the chamber 8%? during the return travel of the carriage I29 is always under fluid pressure and the piston 82 moves toward the left. Under these new conditions which are the result of moving the lever I5 into the position B all of the fluid in the chamber 8 may drain directly into the sump II! by means of the passages E88, 20, I6I2, IEIS and 2I. The quantity of the fluid expelled from chamber can is now no longer limited by the capacity of chamber W5 and the piston 82, therefore, does not only move a distance U (Fig. 15) but moves the entire distance which is available to it and which is designated with V in Fig. 16. When this happens there will be produced a greater distance between the grinding worm IE1 and the press roll Iii-i so that an exchange of the truing and dressing device may take place without difficulty. If, however, the grinding worm i8 is to be again worked upon by the press roll I54, then it will be necessary to move the lever I5 again into the position A. This causes an engagement of the two spur gears 25 and I I. Since now the carriage I20 was stopped between the points H and I the carriage, upon reconnection of the driving mechanism, will continue its travel toward the left. At the point I it starts in the manner described its travel toward the right. At the point K the piston 82 executes its radial feed movement, but itshould be realized-that at this time thepiston 82 does not only move a distance U but it moves the total stroke V. All other functions will now be repeated without change as already described.

After the rolling of the grinding worm II] has been completed it will be necessary to dress the sides of the grinding worm helix with the diamonds I68, use so that all and any inaccuracies in the profile may be removed.

For this purpose the press roll device is removed from the carriage I29 and the diamond dressing device is attached in place thereof on the carriage I26 and is secured in position by the screws I63 (Fig. 3). Since it will not be necessary to rotate the spindle 5 during the diamond dressing operation the hand lever I52 is moved into the position D. This adjustment of the hand lever IE2 has the result that the lever I00, and the pin 99 which engages the groove 98I displaces the spur gear 58 a suficient distance that it no longer meshes with the spur gear 92. Therefore, any feed steps which the piston IIi i transmits to the feed wheel I03 and the ratchet wheel on the shaft 94 "are no longer transmitted to the spindle 9|. 

